What most don't know, is that both RJ and Natalie were extremely jealous of each other, and the 'closeness' they and with co-stars.
There was clear chemistry between RJ an Stefanie on their show, fostered by their friendship for many years. And the chemistry between Natalie and Walken, who was then a hot commodity, was palpable too.
RJ and Natalie arguing/fighting was certainly nothing new to those who knew them. RJ had been spending time consoling Stefanie Powers, who had just lost William Holden tragically, and Natalie was spending all her time on the set of 'Brainstorm' with Walken.
Oh, a little known fact: Natalie Wood, Jill St. John, and Stefanie Powers all have another thing in common besides their love for Wagner- they attended dance school at the same time as young girls.
Their lives would intersect numerous times, including all four of them appearing in the pilot movie for Hart to Hart in 1979. Natalie's cameo was credited under her real name.
Of interest.